Antislip foot



E. SCHMIDT ANTISLIP FOOT May 4, 1943.

Filed April 29, 1940 2 Sheets-Sheet l m 2 0 e 3W5 K V F m a w w w Patented May 4, 1943 U i D STT S AN TISLIP FOOT Eugene Schmidt, Oak Park, 111., assignor to Charles 0. Moore Application April 29, 1940, Serial No. 332,232

10 Claims.

It is an object of my invention to provide an anti-slip device adapted to be secured to a leg of a ladder or the like and provide a sure and adequate grip on a support irrespective of the inclination of the ladder to the vertical.

It is another object to provide a foot having relatively yielding and rigid gripping means selectively usable irrespective of the relation of the leg to the supporting surface and on different kinds of such surfaces.

A further object resides in the provision of a reinforced rubber foot.

Another object is to provide a foot structure which is readily adjustable to insure proper division of the load on the various feet, irrespective of the supporting terrain.

It is a further object to provide an improved means by which an anti-slip device may be securely mounted on a ladder leg or the like.

Additional objects and advantages of the invention will appear as the description proceeds.

My invention will be better understood upon reference to the following description and accompanying drawings, in which:

Fi 1 is a fragmentary side elevation of a ladder equipped with an anti-slip foot device in accordance with one form of my invention, the ladder being shown at an exaggerated inclination.

Fig. 2 is a fragmentary side elevation of the upper part of the same.

Fig. 3 is a fragmentary rear elevation taken as indicated by the line 33 in Fig. 2.

Fig. 4 is a bottom plan view taken as indicated by the line 4-4 in Fig. 1.

Fig. 5 is a sectional plan view taken as indicated by the line 5-5 in Fig. 1.

Fig. 6 is a fragmentary section elevation taken as indicated by the line 6-6 in Fig. 1.

Fig. '7 is an isometric view of the shell forming a part of th structure shown in Fig. 6.

Fig. 8 is a fragmentary sectional view taken as indicated by the line 8--8 in Fig. 6 but with the shell in the position shown in dotted lines in Fig. 6.

Fig. 9 is a fragmentary longitudinal sectional view of a modified form of the invention.

Fig. 10 is a fragmentary elevation showing a modified adjusting means.

Figs. ll, 12 and 13 are fragmentary elevations showing how the invention is useful on different kinds of supporting surfaces.

Referring now more particularly to the drawings, there is shown at l5 by way of example a I ladder which is adapted to be securely supported on a surface l6 which may incline transversely (Fig. 11) and/or parallel (Fig. 12) to the supporting wall or on any other surface or surfaces I! (Fig. 13) for the purpose of illustrating the adaptability of my invention to difficult conditions. The forms to be described may be used interchangeably on the various types of supporting surfaces. Mounted on each rail N3 of the ladder is an anti-slip device l9 constructed in accordance with one form of my invention.

The device l9 comprises a preferably metallic bracket 2| adapted to lie against the outer face .22 of the associated rail l8 and provided with spaced upper and lower sleeves 24 and 25 which receive a preferably metallic rod 21 threaded at 28 throughout a substantial portion of the length thereof. According to one form of my invention, an adjusting nut 30 between the sleeves 24 and 25 and threaded about the rod 21 and knurled or provided with wrench holes 3! is rotatable by hand or a tool to adjust the rod up and down. If desired, the nut as shown at 3011. in Fig. 10 may have a miter gear connection 3la.with a, handle or knob 3lb, supported as by a bracket 3lc carried by the bracket 2|, whereby rotation of the knob will control the adjustment of the rod 21. The rod is preferably slidably keyed or other suitable provision is preferably made to prevent rotation of the rod. For example, the sleeves 24 and 25 may be provided with grooves or keyways 32 and 33, respectively, and pins or screws 36 and 35, respectively, may be secured to the rod 21 so that the heads of the pins are slidable in the respective grooves. The arrangement is such that at no time are both pins disengaged from the grooves, thus insuring prevention of turning of the rod at all-times. Moreover, the nut provides an abutment engageable by the pin 34 to limit the downward movement of the rod 27,, and also engageable by the pin 35 to limit the upward face, said beads being suction cupped as at 4| if desired. A metal reinforcing liner 42 is molded integral with the tread 39 and provides a substantial part of the ball-bearing area of the socket 38. The liner preferably has an outwardly extending flange 43 with a preferably downwardly extending lip 45, whereby to distribute the load from the ball to substantially the entiresubstance of the tread member 39. The rubber material converges upwardly from the liner to provide a resilient retaining lip 46 embracing the ball, said lip being expansible by the ball to admit the ball to the socket and having a circumferential outer groove 48 in which is received a preferably metallic endless ring 49 which may tightly embrace the lip. This ring is preferably shoved into place after the ball has expanded the lip 46 and slipped fully into the socket. The ring thereafter prevents the lip 46 from expanding sufficiently to permit separation of the tread 39 from the ball. The lip serves also as a limit to the relative inclination of the foot and rod.

Telescopically fitted about the tread 39 is a shell or sleeve 50 having an inwardly overhanging integrally connected flange I. Between this flange and a shoulder 53 on the tread 39 is a spring 54, which may be under compression. This spring is operative to urge the sleeve upward relative to the tread 39. The sleeve is provided with inwardly projecting lugs or tongues 56 accommodated in complemental recesses 51 in the lower part of the tread when the latter is in service.

Each tongue 56 has end flanges 80 providing sockets 6| in which the bottom portions 62 of the lugs 63 alternating with the recesses. 51 are adapted to seat, when the sleeve is depressed sufficiently to enable the tongues to clear the lugs and then turned substantially through the angle subtended by a lug 63, bayonet fashion. The tongues 56 carry prefe ably steel or other metallic spikes 65 which project substantially below the element 39 when the lugs 63 of the latter are seated in the sockets 6|. By reversing the bay onet action, the sleeve maybe made to occupy its inoperative position. Thus when the ladder is supported on an icy or earthy or other surface adapted to be better gripped by the spikes than by the rubber element, the sleeve 50 is adjusted to project the spikes below the rubber (Fig. 6 in dotted lines, and Fig. 8), and when surfaces on which the latter affords a better grip are encountered. the sleeve is shifted to inoperative position (Fig. 6 in full lines).

Inasmuch as the foot 31 is universally mounted. its entire gripping portion, whether yieldable or rigid, is certain to engage the supporting surface, the load being transmitted to each foot from the associated ladder rail I8, bracket 2I, nut and rod 21. The load is incident on the liner 42, which, as explained, distributes the load so thoroughly in the rubber element 31 that substantially all of the beads or spikes 65, as the case may be, exert substantial gripping pressure. thereby firmly anchoring the ladder to its support. By the adjusting means referred to, the foot 31 may be adjusted to any height desired to insure that each foot takes its share of the load and to enable the ladder rungs 68 to be horizontal and the upper ends of the rails to engage the wall against which the ladder is leaning.

The securement of the bracket 2I on rails of different sizes forms a feature of my invention. To this end I provide, preferably adjacent each end of the bracket, lugs 13 preferably non-rotatably receiving nuts I4 on bolts 18 extending through said lugs, said bolts also extending through and clamping ears ll of clamp members I9 against the front and rear faces and 8|, respectively, of the rail. Each member I9 has another clamping ear 82 at a right angle to the ear I1 and engaging the bracket 2I. A like pair of clamping members 19a having corresponding ears Ila and 82a is similarly disposed with respect to the other corner portions of the rail. A bolt 84 clamps each pair of clamp ears 82 and 821: against the bracket 2| and opposite face 85 of the rail, and another bolt 81 clamps the ears I'Ia,against the front and rear faces 80 and 8| of the rail. It is evident from the drawings and the foregoing description that the clamp members and bracket are so dimensioned that they may be securely clamped to rails of different cross-sectional sizes and at any desired positions along the rails. The clamping faces may be knurled or otherwise roughened to securely grip the rails.

A plurality of clamp mechanisms may be employed, as shown with one adjacent each end of the bracket 2|, or otherwise. The bottom of the bracket 2| is preferably provided with a flange to abut the bottom 9| of the rail I8, and with a reinforcing boss or lug 93 projecting into a complemental recess or opening 94 in the bottom of the rail.

In accordance with another form of anti-slip device I00 (Fig, 9) embodying my invention, I employ, instead of the universal foot mounting heretofore described, a foot IOI comprising a rubber or other suitable resilient tread element I03 reinforced by a steel or other metal sleeve or cup I04 integrally molded thereto. Thus the sleeve I04 may form one of the molding members for the element I 03. The ground-engaging surface I 05 of the tread element is preferably spherical or otherwise convex and preferably comprises beads I06 which may be vacuum cupped as at I01.

Instead of the rod 21, I employ in this form a sleeve I08 threaded externally as at I09 and extending through the sleeves H0 and I II of a bracket II2 similar to the bracket 2| and receiving a nut H6 whereby the sleeve I08 may be adjusted up and down. The sleeve I08 has its bottom H4 projecting below the bracket H2 and resting on a shoulder I I5 in the tread-reinforcing cup I04, the sleeve being secured in the cup by any suitable means, such as a set screw I IT.

The sleeve I08 is internally threaded as at '9 and a rod I20 threaded as at I2I engages the interior thread of the sleeve. The rod I20 projects above the sleeve I08 and has a knob or handle I23 for rotation thereof. The bottom of the rod is in the form of a spike I25 which may project down through registering holes I21 and I28 in the cup I04 and tread element I03, respectively, or may be retracted upward to a point above the bottom of the tread as shown in dotted lines.

Since the thread friction on the rod I 20 is likely to be less than the friction between the nut I I6 and the bracket sleeves H0 and III, and the thread friction between the nut I I6 and the sleeve I08, when the anti-slip device is free of the ground, and certainly is less than the friction between the tread element I 03 and the ground or the like if the anti-slip foot IN is on the latter, rotation of the rod I20 will cause the same to rise or descend, as desired. In practice, if the anti-slip foot'is free of the ground or the like,

the user will grasp the foot IBI while he rotates the rod I20 or the nut H6.

As in the form previously described, the bracket.

H2 preferably has keyways I30 and I3! accomirrespective of the inclination of the plane of the ladder.

Various modifications may suggest themselves to those skilled in the art without departing from the spirit of my invention, and, hence, I do not wish to be restricted to the specific form shown or uses mentioned, except to the extent indicated in the appended claims, which are to be interpreted as broadly as the state of the art will permit.

I claim:

1. An anti-slip device, comprising a resilient rubber foot having a socket of greater than hemispherical extent, a supporting member having a metal ball anchored in said socket, a hemispherical metal shell lining the base of said socket-and in bearing engagement with said ball, said shell having a. rim flange imbedded in said rubber whereby the load from said ball is distributed throughout a substantial part of the rubber, and a relatively rigid band surrounding said rubber beyond said shell'for preventing removal of said ball from said socket.

2. An anti-slip device, comprising a resilient rubber foot having a socket of greater than hemi spherical extent, a supporting member having a metal ball anchored in said socket, and a hemispherical metal shell lining. the base of said socket and in bearing engagement with said ball,

- said shell having a rim flange imbedded in said of said socket adjacent the mouth thereof to prevent separation of said foot from said ball.

4. An ariti-slip device, comprising a bracket, means -for mounting said bracket on a ladder rail, a pair of gripping members, one of said members being carried by said bracket, the other of said members being carried by said one member, and means for relatively adjusting said members to supported on the other, means comprising a universal support for the supporting member, and means for relatively adjusting said members to render either of them selectively operative.

6. An anti-slip device, comprising a resilient rubber gripping member, a spiked relatively rigid gripping member, an element adapted for connection to a ladder rail, a ball-and-socket connection between one of said members and said element, and bayonet means connecting said members together, whereby either of saidmembers may be selectively disposed lowermost.

7. An anti-slip device comprising a resilient rubber gripping member and a spiked relatively locate either of said members selectivelyinop-Y erative position.

' 5. An anti-slip device, comprising a pair of coaxially related gripping members, one of said members being relatively soft and the other'being-relatively rigid, one ofsaid members being,

rigid gripping member, means connected to said device for transmitting load from a ladder to said device, and means connecting said members together for selective operation of said mem bers, said rubber member transmitting load regardless whether it or the other member is in gripping position.

8. An anti-slip device, comprising a resilient rubber gripping member, a relatively rigid shell about said member, said member having recesses from the bottom upward at least part way, and

intervening lugs, said shell. having tongues slidably received in said recesses, said shell being shiftable to project its tongues below said recesses. and laterally to locate its tongues below said lugs, means for preventing lateral displacement between said tongues and lugs, spikes projecting down from said tongues, said spikes projecting below said rubber member when. said tongues are below said lugs, said spikes terminating above the bottom of said rubber member when said tongues are in said recesses, and means yielda-bly holding said tongues in the selected positions.

9. An anti-slip device, comprising a bracket adapted to be attached to a ladder rail, a resilient rubber gripping member having gripping means disposed substantially in a plane, a balland-socket connection between said rubber membar and said bracket, means for vertically adjusting said connection, and a relatively rigid gripping member having gripping spike points disposed substantially in a plane and supported by said rubber member in selectively operative and inoperative positions.

10. An anti-slip device, comprising a resilient rubber gripping member, a relativelyrigid gripping member. having ground penetrating means. I means operatively connecting said members to-, g'ether in coaxial relationand to a'-' la'ddenrail, and means for relatively adjustingsai'd members to dispose either of said members in operative and the other in inoperativeposit'ion, selectively, I said adjusting means being'operative to prpiet. and maintain said penetrating means in pene-Q trating positions at different distances beyond said resilient member.

EUGENE SCHMIDT. 

